Orthodontic treatment generally involves attaching appliances to teeth, and then adjusting those appliances to move the teeth into desired positions and orientations. Such appliances typically include braces attached to the teeth, and wires connected to the braces. Adjustments are made to the wires, which cause forces to be applied to the teeth, which in turn move the teeth. In some cases, an individual may have replacement teeth, which may be permanent or temporary.
After the desired positions and orientations of the teeth have been achieved, in most instances, additional appliances, called retainers or retention systems, are used to retain the teeth in the corrected positions and orientations. Occasionally, such retainers or retention systems have a secondary function of moving the teeth. Currently used types of retainers include plastic, thermo-formic, removable retainers, which are formed to the shape of an individual's mouth and include wires to retain the teeth in the desired positions and orientations. Other retainers include brackets cemented to the teeth, with fixed wires attached to the brackets.